Adjust button behaviors: History section-header hover style + clear buttons out of tab order #1487

Summary

Two small button-behavior adjustments in the web client.

1. History section headers — use the filter-button hover style

On the History screen, when both the Pinned Requests and History sections are present, each section header is a collapsible "pleat" bar (HistoryListPanel / SectionHeaderBar). Today that bar uses the list-item hover treatment (a background fill on hover, via the sectionHeader Group variant → .list-item).

Change it to use the same style as the filter toggle buttons (Logging / History / Network): a thin outline (border) on hover rather than a background fill, while keeping the filled background for the open/active section. This makes the section headers consistent with the filter buttons and keeps hover visually distinct from the active state (same rationale as #1460).

2. Take input clear buttons out of the tab order

PR #1448 added a clear (×) CloseButton to many text inputs across the app (via rightSection). These clear buttons are currently in the keyboard tab order, so when filling out a form, pressing Tab to move to the next field instead lands on the clear button — annoying.

Add tabIndex={-1} to every input clear button so they remain mouse-clickable but are skipped during keyboard tab navigation. This covers all aria-label="Clear" CloseButton instances plus the Autocomplete clear button enabled app-wide in #1448 (theme/Autocomplete.ts).

(The Select clearable clear buttons predate #1448 and are out of scope.)

Acceptance criteria

• History section headers (Pinned / History) show an outline on hover, matching the filter toggle buttons; open section keeps its filled background.
• All input clear buttons added in feat(web): add Mantine clear buttons to text inputs app-wide (#1333) #1448 are removed from the keyboard tab order (Tab skips them).
• Tests/format/lint/typecheck/build pass.